This study will examine whether low doses of vaginal estradiol exert only local effects on the vaginal and urethral mucosa without systemic absorption of estradiol; so that symptoms of urogenital atrophy are improved without side effects of systemic therapy (i.e. potential risk of breast cancer). Twenty-five postmenopausal women with urogenital atrophy will be studied, 5 in each cohort. The five cohorts will be as follows: 10 mcg, 5 mcg, 2.5 mcg and 1.25 mcg doses and placebo. Ongoing study.